Control valve



Sept. 2, 1969 o. a. CRUSE 3,464,742

CONTROL VALVE Filed March 2 1968 INVENTOR OLIVER B. CRUSE BY US. Cl. 30313 12 Claims ABSTRACT OF THE DISCLOSURE A control valve having application means movabl therein to establish service fluid pressure for normally effecting service energization of the vehicle brakes, other application means normally applying emergency fluid pressure to spring set brake cylinders to maintain th spring-driven member thereof disabled and operable by the first named application means upon the failure of the service fluid pressure to effect the actuation of the spring-driven member, and operating means responsive to the established service fluid pressure for moving said other application means to a position exhausting the emergency fluid pressure from the spring set brake cylinders to permit actuation of the spring-driven member thereof for effecting mechanical actuation of the vehicle brakes.

This invention relates to control valves and in particular to those control valves for use in fluid pressure systems utilizing spring set devices.

In the past, control valves were provided with primary or service application means movable in response to an applied force to normally apply primary or service fluid pressure to the fluid pressure responsive member of a spring set operating cylinder or motor and effect a normal or service energization of the device connected therewith under normal operating conditions, i.e., when the service fluid pressure was available. The control valve was also provided with auxiliary or emergency application means for applying auxiliary or emergency fluid pressure to the spring set operating cylinder to normally maintain the spring-driven member thereof in the inoperative or disabled position, and said emergency application means was driven by the service application means upon the applied force movement thereof in excess of a predetermined amount, such as for instance under emergency operating conditions in the event of the failure of the service fluid pressure, toward a position isolating the applied emergency fluid pressure from its source and effecting metered exhaustion of the applied emergency fluid pressure from the spring set operating cylinder to permit actuation of the spring-driven member for effecting mechanical energization of the device connected therewith. However, in some of the heavier equipment, such as earth-moving vehicles or the like, for example, it is desirable not only to actuate the emergency application means under emergency operating conditions but also to actuate said emergency application means under normal operating conditions in order to obtain the compounding or assisting mechanical energization of the devices in addition to the normal service energization of the devices. Also, in other equipment, including industrial equipment, it is desirable to actuate the emergency ap plication means not only under emergency operating conditions but also under normal operating conditions in order to utilize the emergency fluid pressure for actuating auxiliary or ancillary devices whose operation is independent of but related to the first named devices. From the foregoing, it is obvious that a disadvantageous or undesirable feature of the past control valve constructions was that they were unable to effect controlled actuation of their auxiliary application means by their primary apnited States Patent plication means under normal operating conditions, i.e., when the primary fluid pressure was available; and the principal object of the present invention is to provide a control valve which overcomes the aforementioned disadvantageous or undesirable feature, and this, as well as other objects and advantageous features of the present invention, will become apparent in the specification which follows.

Briefly, the present invention embodies a control valve having application means movable between one position effecting the application through said control valve of fluid pressure supplied thereto and another position iso lating the supplied fluid pressure and effecting a reduction in the magnitude of the applied fluid pressure, and other means responsive to the establishment of other applied fluid pressure for moving said first named application means toward its other position. Another aspect of the present invention embodies other application means movable in response to an applied force to effect the application through said control valve of another fluid pressure supplied thereto for establishing the other applied fluid pressure, and means defining a force transmitting connection between said other application means and said other means for moving said first named application means to its other position in the event of the failure of the last named applied fluid pressure.

In the drawing, wherein like numerals refer to like parts wherever they occur, a sectional view is provided illustrating a control valve embodying the present invention in cross-section.

Referring now to the drawing in detail, a control valve 1 is provided with upper, intermediate and lower housings 2, 3 and 4 which are connected by suitable means, such as studs 5. The upper housing 2 is provided with a bore 6 defining an annular wall or partition 7 axially positioned between a counterbore 8 and stepped counterbores 9 which respectively define a set of inlet and outlet chambers, and a valve seat 10 is defined on said wall in circu-mscribing relation with said bore. A set of service inlet and outlet ports 11, 12 are provided in the upper housing 2 respectively intersecting with the counterbore 8 and the smaller of the stepped counterbores 9, and a recess 13 is provided in the upper end portion of the intermediate housing 3 beneath the counterbore 8 forming an exhaust chamber communicating with an exhaust port 14 in the upper housing 2. A valve guide member 15 is received in the lower end of the counterbore 8 in displacement preventing engagement with a shoulder 16 provided on the intermediate housing 3 in the recess 13 thereof. The valve guide member 15 is provided with a bore 17 in which a valve element or member 18 is slidable, and seals 19, 20 are carried by said valve guide element in sealing engagement with the counterbore 8 and said valve element, respectively. The valve element 18 is provided with an axial bore or vent passage 21 therethrough, and an annular sealin member or disc 22 is provided on the upper end of said valve element in circumscribing relation with said vent passage, said sealing member being normally urged into sealing engagement with the upper housing valve seat 10 by a valve spring 23 biased between said valve element and the valve guide member 15.

An application or valve control member, such as the service piston 24, is provided with a peripheral seal 25 and is slidably received in the stepped counterbores 9. The service piston 24 is provided with a valve seat 26 on the lower end thereof which is coaxial with the upper housing bore 6 and normally maintained in spaced relation with the valve element seal 22 by a return spring 27 biased between said service piston and the upper housing 2. A metering spring bore 28 is provided in the service piston 24, and a pre-compressed metering spring 29 is retained therein against displacement by a retainer or treadle force receiving plate 30 which is biased into abutment with a. snap ring and groove assembly 31 provided in the upper end of said metering spring bore.

The intermediate housing 3 is provided with a bore 32 having a seal 33 disposed therein, said bore being interposed between a counterbore 34 also provided in said intermediate housing 3 and the recess 13, and a shoulder 35 is defined on said intermediate housing at the juncture of said bore and counterbore 32, 34. A passage 36 is provided in the upper and intermediate housings 2, 3 having one end thereof connecting with the upper housing outlet chamber in open pressure fluid communication with the outlet port 12 and the lower end thereof intersecting with the intermediate housing shoulder 35, and an atmospheric port or passage 37 is provided in said intermediate housing intersecting said counterbore 34 adjacent to the lower end thereof.

An intermediate or operating member, such as the control piston 38, is provided with a peripheral seal 39 and slidably received in the intermediate housing counterbore 34, and an expansible fluid pressure or control chamber 40 is defined in the intermediate housing counterbore 34 between the shoulder 35 and the upper end 41 of the intermediate piston 38, said chamber being connected in open pressure fluid communication with the housing passage 36. The lower end 42 of the control piston 38 is subjected to the atmosphere at the atmospheric port 37 at all times. A stem or driven member 43 is integrally formed with the upper end 41 of the control piston 38, said stem being slidably received in the intermediate housing bore 32 in sealing engagement with the seal 33 and extending coaxially into the valve element bore 21, and an upper or driven abutment end 44 is provided on said stem in predetermined spaced relation with the seat 26 of the service piston 24 for lost motion driven engagement therewith, to be discussed hereinafter. The upper end 41 of the control piston 38 defines an eflective area A, for subjection to the fluid pressure in the control chamber 40.

Another bore 45 having a seal 46 disposed therein is provided in the lower housing 4 connected between another counterbore 47 also provided in said lower housing and the intermediate housing counterbore 34. Another shoulder 48 is defined on the lower housing 4 at the juncture of the lower housing bore and counterbores 45, 47, and a set of emergency inlet and outlet ports 49, 50 are provided in said lower housing intersecting with said lower housing counterbore adjacent to the lower end thereof and at said shoulder, respectively. Another valve guide member 51 is received in the lower end of the lower housing counterbore 47 and retained therein against displacement by a snap ring and groove assembly 52 provided in the lower end of said counterbore 47. The valve guide member 51 is provided with a bore 53 in which another valve element or member 54 is slidable, and seals 55, 56 are carried by said valve guide member in sealing engagement with the lower housing counterbore 47 and said valve element, respectively. The valve element 54 is provided with an axial bore or vent passage 57 theret-hrough, and an annular sealing member or disc 58 is provided on the upper end of said inlet valve element in circumscribing relation with said vent passage. A seating member 59 extends coaxially through the valve element bore 53 having its lower end fixedly connected with the valve guide member 51 at 60, and the other end thereof defining a valve seat 61 for engagement with the inlet valve seal 58. An exhaust port 62 is also provided in the valve guide member 51 in open communication with the valve element vent passage 53, and a valve spring 62a is biased between the inlet valve element 54 and the valve guide member 51 normally urging the seal 58 of said inlet valve element into sealing engagement with the valve seat 61 to interrupt pressure fluid communication between the emergency outlet port 50 and the exhaust port 62.

An application or valve control member, such as the emergency piston 63, is provided with a peripheral seal 64 therein and slidably received in the lower housing counterbore 47 between the inlet and outlet ports 49, 50. A stem 65, integrally formed with the emergency piston 63, is slidably received in the lower housing bore 45 in sealing engagement with the seal 46 therein, said stem having an upper or driven end 66 extending into the intermediate housing counterbore 34 in driven or abutting engagement with the lower end 42 of the control piston 38. Another inlet chamber 67 is defined in the lower housing counterbore 47 between the lower end 68 of the emergency piston 63 and the valve guide member 51 in open pressure fluid communication with the inlet port 49, and an outlet chamber 69 is defined between the upper end 70 of said emergency piston and the lower housing shoulder 48 in open pressure fluid communication with the outlet port 50, said emergency piston upper end 70 being normally engaged with said upper housing shoulder when said emergency piston is in its normal operating position. A valve seat 71 is provided on the emergency piston lower end 68 for engagement with the valve element 54 about the valve seat 61, and a passage 72 is provided between said emergency piston lower and upper ends 68, 70 having one end connecting with the outlet chamber 69 and the other end thereof extending through said valve seat. It should be noted that the emergency piston 63 is provided with an effective area A substantially defined across the seal 64, an effective area A, substantially defined by the sealing engagement of the valve seat 71 with the valve element 54, and an effective area A on the stem portion 65 substantially defined across the seal 46; therefore, the emergency piston 63 is provided with an effective output area A A which is subjected to the fluid pressure at the emergency outlet port 50 at all times, said output area A A being, of course, opposed to and predeterminately less than the input area A In this manner, the emergency fluid pressure at the emergency inlet port 49 acts on the input area A against the fluid pressure at the outlet port 50, which is of the same magnitude as that of said emergency inlet port, acting on the opposed area A A to establish a predetermined difierential reaction force F, acting across the emergency piston 63 and urging said emergency piston toward its normal operative position; however, when said emergency piston is actuated to engage the valve seat 71 with the valve element 54, as will be fully discussed hereinafter, the fluid pressure at said emergency inlet port acts on the area A2A4 which is less than the area A A subjected to the fluid pressure at said emergency outlet port 50. To complete the description of the control valve 1, it should be noted that said control valve is adapted for connection in a fluid pressure operating system, such as the well-known braking system (not shown) disclosed in US. Patent No. 3,309,149 issued Mar. 14, 1967, to Richard C. Bueler wherein the inlet ports 11, 49 are adapted for respective connection with the usual service and emergency tanks and the outlets 12, 50 are adapted for respective connection with the service and emergency portions of the usual spring set brake cylinder.

In the operation with the component parts of the control valve 1 positioned as shown in the drawing, the emergency fluid pressure at the emergency inlet and outlet ports 49, 50 respectively acts on the opposed effective areas A and A -A to establish the predetermined reaction force F urging the emergency piston 63 upwardly toward its normal or original operating position into engagement with the lower housing shoulder 48 and the stern driven end 56 into engagement with the control piston 38 which, in turn, urges control piston 38 into abutting engagement with the intermediate housing shoulder 35 and positions the driven end 44 of the control piston stem 43 in predetermined spaced relation with the seat 26 of the service piston 24.

If the operator desires to eflect a service braking application of the vehicle under normal operating conditions, i.e., when the service fluid pressure is available, a manually applied force on the force receiving plate 30 of the control valve 1 is transmitted through the metering spring 29 to the service piston 24 to move said service piston downwardly against its return spring 27. This downward movement initially engages the service piston valve seat 26 with the valve element 18 closing the vent passage 21 thereof and isolating the outlet chamber 9 from the atmosphere, and further downward movement thereafter urges said valve element against its return spring 23 to a position disengaged from the housing valve seat 10 to establish pressure fluid communication between the service inlet and outlet ports 11, 12. The service fluid pressure flows from the inlet port 11 through the inlet chamber 8, the upper housing bore 6, and the outlet chamber 9 to the outlet port 12, and when the reaction force created by the established fluid pressure at the outlet port 12 acting on the effective area of the service piston 24 therein equals the manually applied force, said service piston is moved upwardly against the metering spring 29 wherein the valve element 18 is positioned in lapped engagement between the upper housing valve seat 10 and the piston valve seat 26. The reaction force acting through the metering spring 29 affords the operator a direct and accurate feel as to the extent or intensity of the service braking effort or application. At the same time, the established fluid pressure at the outlet port 12 is also transmitted through the housing passage 36 into the intermediate housing chamber 40 acting on the eflective area A; of the control piston 38 therein to establish a control force F When the magnitude of the control force F attains a value great enought to overcome the predetermined reaction force F acting on the emergency piston 63, said control and emergency pistons are concertedly movedw downwardly due to the driving engagement between the control piston lower end 42 and the stem driven end 66 to engage the emergency piston valve seat 71 with the valve element 54 interrupting pressure fluid communication between the emergency inlet and outlet ports 49, '50 and thereafter moving said valve element against its spring 62a toward a position disengaged from the exhaust valve seat 61 to establish metered pressure fluid communication between the emergency outlet port and the exhaust port 62 through the valve element vent passage 53. Due to the engagement of the valve seat 71 with the valve element 5-4 to isolate the fluid pressure at the emergency inlet port 49, such isolated fluid pressure now acts on the emergency piston input area A A against the fluid pressure at the emergency outlet port 50 acting on the emergency piston output area A A and the emergency fluid pressure flows from the emergency outlet port 50 through the outlet chamber 69, the emergency piston passage 72 and the valve element vent passage 53 to the atmosphere through the exhaust port 62. The reduction of the emergency fluid pressure at the emergency outlet port 50 acting on the effective emergency piston area A A serves to increase the magnitude of the reaction force F in excess of the predetermined value thereof, and when the increased reaction force F attains the magnitude of the control force F the control and emergency pistons 38, 63 are concertedly moved upwardly toward a position wherein the valve element 54 is seated in lapped engagement with the exhaust valve seat 61 and the emergency piston valve seat 71. From the foregoing, it is obvious that the service fluid pressure established at the outlet port 12 must attain a predetermined magnitude to establish a control force F great enough to overcome the predetermined reaction force F acting across the emergency piston 63. In other words, before the emergency piston 63 can be actuated it is manifest 0 establish a service fluid pressure of a predetermined magnitude which, in effect, permits actuation of the motor (not shown) connected with the outlet port 12 prior to the actuation of the motor (not shown) connected with the emergency port 50. Also, when the control valve 1 is connected in the system (not shown) of the aforementioned US. Patent No. 3,309,149, the emergency fluid pressure at the outlet port 50 must be reduced to a predetermined value before the spring-driven member of the friction device operating cylinder is mechanically operative; therefore, it is obvious that a greater service pressure at the outlet port 21 is necessary to effect the actuation of the spring-driven member under normal operating conditions.

If a greater service braking application is desired, the manually applied force is increased which results in an increased control force F and the component parts of the control valve 1 function in the same manner as previously described. When the desired service braking effort is attained, the manually applied force is removed from the service piston 24, the reaction force of the service fluid pressure at the service outlet port 12 acting thereon and the additive force of the return spring 27 moves said service piston upwardly toward its original position disengaging the valve seat 28 thereof from the valve element 18 to again open the valve element exhaust passage 21 re-establishing pressure fluid communication between the outlet and exhaust ports 12, 14 to exhaust the established fluid pressure through the outlet chamber 9, the upper housing bore 6, the valve element vent passage 21, and the housing recess 13 to the atmosphere which eliminates the reaction force on said service piston. At the same time, the established fluid pressure in the control chamber 40 is also exhausted through the housing passage 36 into the outlet chamber 9 and therefrom to the exhaust port 14, as described hereinabove, to eliminate the control force F Upon the elimination of the control force F the increase reaction force F moves the reaction piston 63 upwardly to its original position engaged with the lower housing shoulder 48 and disengaging the valve seat 71 from the valve element 54 to re-establish open pressure fluid communication between the emergency inlet and outlet ports 49, 50. With the valve seat 71 disengaged from the valve element 54 and the emergency piston 63 in its normal position, the magnitude of the reaction force F is reduced to its predetermined value since the emergency fluid pressure at the emergency inlet port 49 now acts in the emergency piston area A and the emergency fluid pressure at the emergency outlet port 50, having substantially the same magnitude as that of the emergency fluid pressure at said emergency inlet port, acts on the opposed emergency piston area A -A and the upward or return movement of said reaction piston concertedly drives the control piston 38 to its original position engaged with the intermediate housing shoulder 35.

Under emergency operating conditions, i.e., in the event of the failure of the service fluid pressure at either the service inlet or outlet ports 11, 12,, it is, of course, obvious that the applied force movement of the service piston 24 to actuate the valve element 18 fails to establish the necessary service fluid pressure to effect actuation of the control piston 38; however, further applied force movement of said service piston engages the seat 26 thereof with the driven end 44 of the control piston stem 43 to thereafter effect concerted applied force movement of said control piston and the emergency piston 63 therewith against the predetermined reaction force F acting across said emergency piston in opposition to the applied force. Under such emergency conditions, the concerted applied force movement of the service, control and emergency pistons 24, 38-, 63 actuates the valve element 54, as described hereinabove, to isolate the fluid pressure at the emergency inlet port 49 and reduce the emergency fluid pressure at the emergency outlet port 511 which, of course, serves to increase the reaction force F When the increased reaction force F, attains a magnitude substantially equal to the applied force, the service, control and emergency pistons 24, 38, 63 are moved upwardly against the metering spring 29 toward a lapped position wherein the valve element 54 is positioned in lapped engagement with the exhaust valve seat 61 and the emergency piston valve seat 71. If a greater emergency braking application is desired, the manually applied force is increased and the component parts of the control valve 1 function in the same manner as previously described under such emergency conditions. When the desired emergency braking eflort is attained, the manually applied force is removed from the service piston 24 and the increased reaction force F concertedly moves the service, control and emergency pistons 24, 38, 63 upwardly to their original positions to reestablish open pressure fluid communication between the emergency inlet and outlet ports 49, 50 wherein the magnitude of the reaction force F is again reduced to its predetermined value.

It is now apparent that a novel control valve 1 meeting the objects and advantages set out hereinbefore, as well as other advantageous features apparent from the specification, is provided and that changes in the precise configurations, shapes or details of the construction set forth in the disclosure by Way of illustration may be made by those skilled in the art without departing from the spirit of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A control valve comprising a housing, application means movable in said housing between one position effecting the application through said housing of fluid pressure supplied thereto and another position isolating the supplied and applied fluid pressures and metering the applied fluid pressure to the atmosphere, opposed differential areas on said application means respectively subjected to the supplied and applied fluid pressures to establish a reaction force having a predetermined value and opposing movement of said application means from its one position, said application means being movable toward its other position in response to an applied force in excess of the predetermined value of the reaction force and said opposed areas being respectively responsive to the isolated supplied fluid pressure and the reduced applied fluid pressure when said application means is in its other position to increase the reaction force in excess of the predetermined value thereof, other means movable in said housing for driving engagement with said application means, and said other means defining with said housing a chamber for other applied fluid pressure selectively subjected thereto, said other means being responsive to the other applied fluid pressure in excess of a predetermined value in said chamber when selectively subjected thereto to establish the applied force for moving said application means toward its other position against the reaction force.

2. The control valve according to claim 1, comprising other application means movable in said housing in response to another applied force to efiect the application through said housing of another fluid pressure supplied thereto, passage means in said housing for passing the other applied fluid pressure into said chamber, and means for force transmitting engagement between said other means and said application means responsive to the applied force movement of said other application means in excess of the predetermined amount to actuate said first named application means in the event of the failure of the other applied fluid pressure.

3. A control valve comprising a housing, application means movable in said housing between one position effecting the application through said housing of fluid pressure supplied thereto and another position isolating the supplied and applied fluid pressures and metering the applied fluid pressure to the atmosphere, opposed differential areas on said application means respectively subjected to the supplied and applied fluid pressures to establish a reaction force having a predetermined value and opposing movement of said applictaion means from its one position, said application means being movable toward its other position in response to an applied force in excess of the predetermined value of the reaction force and said opposed areas being respectively responsive to the isolated supplied fluid pressure and the reduced applied fluid pressure when said application means is in its other position to increase the reaction force in excess of the predetermined value thereof, other application means movable in said housing in response to an applied force to effect the application through said housing of another fluid pressure supplied thereto, and means for force transmitting engagement between said first named and other application means responsive to the applied force movement of said other application means in excess of a predetermined amount to move said first named application means toward its other position and transmit the reaction force to said other application means in opposition to the applied force thereon, said last named means including other means movable in said housing and defining therewith an expansible fluid pressure chamber connected in communication with the other applied fluid pressure, said other means being responsive to the other applied fluid pressure in excess of a predetermined value in said chamber upon the actuation of said other application means to drive said first named application means toward its other position, and said last named means being responsive to the applied force movement of said other application means in excess of the predetermined amount to actuate said first named application means in the event of the failure of the other applied fluid pressure.

4. The control valve according to claim 1, comprising abutment means on said housing defining the one position of said application means, said application means being normally urged in response to the reaction force acting thereon into engagement with said abutment means.

5. The control valve according to claim 1, comprising inlet and outlet ports in said housing respectively subjected to the supplied and applied fluid pressures, valve means normally urged toward a position in said housing interrupting pressure fluid communication between said outlet port and the atmosphere, said application means including a valve control member for operative engagement with said valve means and normally urged in response to the reaction force toward its one position disengaged from said valve means to establish pressure fluid communication between said inlet and outlet ports, said valve control member being movable in response to the applied force to initially engage said valve means interrupting pressure fluid communication between said inlet and outlet ports and thereafter actuate said valve means to establish pressure fluid communication between said outlet port and the atmosphere and effect the metered reduction of the applied fluid pressure.

6. The control valve according to claim 5, comprising a valve seat on said valve control member and disengaged drom said valve means when said valve control member is in its one position, and passage means in said valve conrtrol member having one end connected in pressure fluid communication with said outlet port and the other end thereof extending through said valve seat for connection in pressure fluid communication with the inlet port when said valve control member is in its one position, said valve seat being engaged with said valve means to interrupt pres sure fluid communication through said passage means between said inlet and outlet ports and the applied fluid pressure at said outlet port being metered to atmosphere through said passage means upon the actuation of said valve means in response to the applied force movement of said valve control member.

7. The control valve according to claim 6, comprising another valve seat on said housing between said outlet port and the atmosphere, said valve means being normally urged into engagement with said other valve seat interrupting pressure fluid communication between said outlet port and the atmosphere and being disengaged from said other valve seat upon actuation in response to the applied force movement of said valve control member to establish the pressure fluid communication between said outlet port and the atmosphere and effect the metered reduction of the applied fluid pressure at said outlet port.

8. The control valve according to claim 7, comprising an exhaust port in said housing, other passage means in said valve means having one end connected in pressure fluid communication with said exhaust port and the other end thereof for connection in pressure fluid communication with said first named passage means, said other end of said other passage means being closed when said valve means is engaged with said other valve seat and being connected with said first named passage means upon actuation of said valve means in response to the applied force movement of said valve control member to establish pressure fluid communication therethrough between said outlet and exhaust ports and effect the metered reduction of the applied fluid pressure at said outlet port.

9. The control valve according to claim 5, comprising another inlet port in said housing for subjection to another supplied fluid pressure, another outlet port in said housing, other valve means movable in said housing and controlling pressure fluid communication between said inlet and outlet ports, another valve control member movable in said housing for operative engagement with said other valve means, said valve control member being movable in response to another applied force thereon to engage and move said valve means toward a position effecting the application of the other supplied fluid pressure from said other inlet port to said other outlet port, and a connecting passage in said housing between said other outlet port and chamber for subjecting said chamber to the other applied fluid pressure at said other outlet port, and another force transmitting member movable in said housing and connected in lost motion engagement between said other valve control member and said other means, said other force transmitting member being movable in response to the applied force movement of said other valve control member in excess of a predetermined amount to transmit the other applied force to said other means for actuating said first named.valve control member toward its other position in opposition to the reaction force in the event of the failure of the other applied fluid pressure at said other outlet port.

10. The control valve according to claim 5, wherein said valve control member defines with said housing opposed inlet and outlet chambers in said housing respectively connected with said inlet and outlet ports, an exhaust port in said housing, an exhaust passage in said valve means connected in pressure fluid communication with said exhaust port, a seating member extending through said exhaust passage having one end connected with said housing and the other end thereof defining a valve seat, said valve means being normally urged into engagement with said valve seat closing said exhaust passage, another valve seat on said valve control member for sealing engagement with said valve means about said valve seat, and passage means in said valve control member extending through saidother valve seat between said inlet and outlet chambers, said other valve seat being engaged with said valve means to isolate said inlet chamber from said outlet chamber and passage means and said valve means being thereafter disengaged from said first named valve seat to connect said passage means with said exhause passage and effect the metered reduction of the applied fluid pressure in said inlet chamber upon movement of said valve control member toward its other position.

11, A control valve comprising a housing, application means movable in said housing between one position effecting the application through said housing of fluid pressure supplied thereto and another position isolating the supplied and applied fluid pressures and metering the applied fluid pressure to the atmosphere, opposed diflerential areas on said application means respectively subjected to the supplied and applied fluid pressures to establish a reaction force having a predetermined value and opposing movement of said application means from its one position, said application means being movable toward its other position in response to an applied force in excess of the predetermined value of the reaction force and said opposed areas being respectively responsive to the isolated supplied fluid pressure and the reduced applied fluid pressure when said application means is in its other position to increase the reaction force in excess of the predetermined value thereof, inlet and outlet ports in said housing respectively subjected to the supplied and applied fluid pressures, valve means normally urged toward a position in said housing interrupting pressure fluid communication between said outlet port and the atmosphere, said application means including a valve control member for operative engagement with said valve means and normally urged in response to the reaction force toward its one position disengaged from said valve means to establish pressure fluid communication between said inlet and outlet ports, said valve control member being movable in response to the applied force to initially engage said valve means interrupting pressure fluid communication between said inlet and outlet ports and thereafter actuate said valve means to establish pressure fluid communication between said outlet port and the atmosphere and effect the metered reduction of the applied fluid pressure, a bore in said housing interposed between a pair of opposed counterbores, a first shoulder on said housing between said bore and one of said counterbores, a closure member in said one counterbore opposed to said first shoulder and spaced therefrom, a valve bore in said closure member substantially coaxial with said one counterbore and connected therewith, flange means on said closure member defining an exhaust port connected with said valve bore, said inlet and outlet ports connecting with said one counterbore adjacent to said closure member and said first shoulder, respectively, said valve means being slidable in said valve bore and extending into said one counterbore, an exhaust passage extending through said valve means in open pressure fluid communication with said exhaust port, a seating member extending substantially coaxially through said exhaust passage having one end connected with said flange means and the other end thereof disposed in said one counterbore defining a valve seat for said valve means, a valve spring engaged between said closure member and valve means normally urging said valve means into engagement with said valve seat to close said exhaust passage, said valve control member including first piston means slidable in said one counterbore between said inlet and outlet ports, and said opposed differential areas being provided on said first piston means, extension means on said first piston means slidable in said housing bore and extending into the other of said counterbores, a driven end portion on said extension means in said other counterbore, abutment means on said piston means for engagement with said first shoulder, a connecting passage extending through said first piston means, another valve seat on said first piston means about said connecting passage for engagement with said valve means about said first named valve seat, said abutment means being normally urged into engagement with said first shoulder and said other valve seat being disengaged from said valve means to establish the pressure fluid communication between said inlet and outlet ports through said connecting passage in response to the' reaction force urging said piston means toward its one position, a second shoulder on said housing between said housing bore and said other counterbore, said housing defining an end wall of said other counterbore opposed to and spaced from said second shoulder, second piston means movable in said other counterbore between said end Wall and shoulder and having opposed end portions, one of said opposed end portions being drivingly engaged with said driven end of said extension means, an atmospheric chamber defined in said other counterbore between said one opposed end portion of said second piston means and said second shoulder, a vent passage in said housing connecting said atmospheric chamber with the atmosphere, other abutment means on said second piston means and normally urged into engagement with said end wall when said first piston means is in its one position, and another chamber defined in said other counterbore between the other opposed end portion of said second piston and said end wall for other applied fluid pressure selectively subjected thereto, said second piston means being responsive to the other applied fluid pressure in excess of a predetermined value acting thereon when said other chamber is selectively subjected to the other applied fluid pressure to establish the applied force for moving said first piston means from its one position toward its other position against the reaction force to initially engage said other valve seat with said valve means isolating said inlet port from said connecting passage and said outlet port and thereafter disengage said valve means from first named valve seat to connect said exhaust passage and connecting passage in pressure fluid communication between said outlet and exhaust ports and eitect the metered reduction of the applied fluid pressure at said outlet port.

12. The control valve according to claim 11, comprising another inlet port in said housing for subjection to another supplied fluid pressure, another outlet port in said housing, other valve means normally urged toward a position in said housing interrupting pressure fluid cmmunication between said inlet and outlet ports, another exhaust passage in said other valve means and extending therethrough to connect said other outlet port with the atmosphere, another valve control member movable in said housing for operative engagement with said other valve means, said other valve control member being movable in response to another applied force thereon to initially engage said other valve means closing said other exhaust passage to interrupt pressure fluid communication between said other outlet port and the atmosphere and also being thereafter further movable to move said other valve means toward another position in said housing eitecting the application of the other supplied fluid pressure from said other inlet port to said other outlet port, passage means in said housing between said other outlet port and said other chamber and effecting the passage of the other applied fluid pressure from said other outlet port into said other chamber, another bore in said end wall intersecting with said second shoulder and aligned with said other exhaust passage of said other valve means, and a force transmitting member slidab'le in said other bore and extending into said other chamber and said other exhaust passage of said other valve means for lost motion connection between said other valve control member and said second piston means, said force transmitting member being movable in response to the other applied force movement of said other valve control member in excess of a predetermined amount to transmit the other applied force to said other means to concertedly drive said first and second piston means and actuate said first named valve means in the event of the failure of the other applied fluid pressure.

References Cited UNITED STATES PATENTS 3,188,916 6/1965 Beatty 137627.5 X 3,309,149 3/1967 Bueler 303-13 3,394,968 7/1968 Bueler 303-68 MILTON BUCHLER, Primary Examiner JOHN J. MCLAUGHLIN, JR., Assistant Examiner US. Cl. X.R. 

